Can i increase performance on one host?

I have one host with a lot of memory, cpus and disk.
and I have static database of 700gb and 217M records, with only one client querying.
can I increase the search speed?. now I get connection timeout sometimes.

What is the full output of the cluster stats API?

What type of data do you have in the cluster?

What type of queries are you running?

What does resource usage look like when you are querying?

Exactly what resources does the host have? What type of storage are you using? Is there anything else running on the host Elasticsearch runs on?